Neurological phenotypes and treatment outcomes in Eagle syndrome: systematic review and meta-analysis

Background

Eagle syndrome is caused by an elongated styloid process affecting carotid arteries and cranial nerves. Pain, dysphagia, tinnitus, paresthesia (classic subtype), and neurovascular events (vascular subtype) may be triggered by head movements or arise spontaneously. However, Eagle syndrome remains underappreciated in the neurological community. We aimed to determine the most common neurological and non-neurological clinical presentations in patients with Eagle syndrome and to assess the clinical outcome post-surgical resection in comparison to non-surgical therapies.

Methodology

We conducted a systematic review of patient-level data on adults with Eagle syndrome, following PRISMA guidelines. We extracted data on demographics, presenting symptoms, neurological deficits, radiological findings, and treatments, including outcomes and complications, from studies in multiple indexing databases published between 2000 and 2023. The study protocol is registered with PROSPERO.

Results

In total, 285 studies met inclusion criteria, including 497 patients with Eagle syndrome (mean age 47.3 years; 49.8% female). Classical Eagle (370 patients, 74.5%) was more frequent than vascular Eagle syndrome (117 patients, 23.5%, p < 0.0001). Six patients (1.2%) presented with both variants and the subvariant for four patients (0.8%) was unknown. There was a male preponderance (70.1% male) in the vascular subtype. A history of tonsillectomy was more frequent in classic (48/153 cases) than in vascular (2/33 cases) Eagle syndrome (Odds Ratio 5.2, 95% CI [1.2-22.4]; p = 0.028). By contrast, cervical movements as trigger factors were more prevalent in vascular (12/33 cases) than in classic (7/153 cases) Eagle syndrome (Odds Ratio 7.95, 95% CI [2.9-21.7]; p = 0.0001). Headache and Horner syndrome were more frequent in vascular Eagle syndrome and dysphagia and neck pain more prominent in classic Eagle syndrome (all p < 0.01). Surgically treated patients achieved overall better outcomes than medically treated ones: Eighty-one (65.9%) of 123 medically treated patients experienced improvement or complete resolution, while the same applied to 313 (97.8%) of 320 surgical patients (Odds Ratio 1.49, 95% CI [1.1-2.0]; p = 0.016).

Conclusions

Eagle syndrome is underdiagnosed with potentially serious neurovascular complications, including ischemic stroke. Surgical treatment achieves better outcomes than conservative management. Although traditionally the domain of otorhinolaryngologist, neurologist should include this syndrome in differential diagnostic considerations because of the varied neurological presentations that are amenable to effective treatment.

Eagle syndrome: An updated review

Background

This work aims to review the current literature and our experience on vascular Eagle syndrome (ES) that can present misleading clinical presentations and better understand the possible therapeutic strategies.

Methods

We reviewed the existing literature on PubMed from January 1, 2017, to December 31, 2022, including the sequential keywords "vascular AND Eagle syndrome," "vascular AND styloid syndrome," "vascular AND elongated styloid process," "vascular AND stylocarotid syndrome," and "Eagle syndrome AND carotid artery dissection."

Results

38 vascular ES cases, including our experience, were analyzed. The most frequent clinical onset was hemiparesis (n 21, 57%), but other regular clinical presentations were aphasia, loss of consciousness, amaurosis, headache, or a combination of the latter. Massive oral bleeding was reported only once in the literature before our case. Twelve patients were treated with only antiplatelet therapy, either single or double. Nine patients were treated with anticoagulation therapy only. In 14 patients, a carotid artery stent was used, associated with anticoagulation or antiplatelet therapy. In 17 cases, a styloid process (SP) resection was performed.

Conclusion

ES has many clinical presentations, and carotid artery dissection resulting in oral bleeding seems rare. Literature results and our experience make us believe that when dealing with vascular ES, the best treatment strategy is endovascular internal carotid artery stenting with antiplatelet therapy, followed by surgical removal of the elongated SP to prevent stent fracture.

Can Styloid Process and Internal Carotid Artery Anatomy be Used to Predict Carotid Artery Dissection?

BACKGROUND

Carotid artery dissection is a common cause of stroke in the young. It has been related to the association of the carotid artery with fixed neighboring anatomical structures. This study assesses the association between styloid process length, internal carotid artery position and cervical carotid artery dissection (CCAD). This information would provide potential predicative radiological measurements, which could prevent delays in CCAD diagnosis.

METHODS

Retrospective data was collected from 2 central London hospitals over 5 years. CCAD cases were identified from individuals who underwent computer topography angiography of the neck for suspected CCAD. The following data was collected: evidence of CCAD; bilateral styloid process length and presence of styloid-hyoid ligament calcification; bilateral styloid process-internal carotid distance; calcification of carotid arteries and whether their position was aberrant. Cases were dissection-side, age and gender matched with two non-dissection controls.

RESULTS

Three hundred and fifty-five individuals were identified. Fifty individuals had CCAD, of which 4 had bilateral dissection. In individuals with CCAD, average styloid process length was 27.5 mm and styloid process-internal carotid distance was 5.14 mm. There was no significant association between styloid process length or styloid process-internal carotid distance, and CCAD when compared with matched controls. Internal carotid artery aberrancy was significant for nondissection.

CONCLUSIONS

In this study, there was no association between styloid process length and styloid process-internal carotid distance with CCAD. These measurements can not be used to predict the possibility of a CCAD following trauma.